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Color & B&W Densitometers



 
 
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  #1  
Old March 3rd 10, 06:57 AM posted to rec.photo.darkroom
[email protected]
external usenet poster
 
Posts: 428
Default Color & B&W Densitometers

Peter wrote:
On Mar 2, 6:07 pm, jay wrote:
Hi all
I want to buy a used color & B&W Densitometer that will work in both
the transmission & reflected mode @ a fairly low price. (Say $400)
I've visited X- Rites web site, & leave w/ my head spinning. I have
the impression that some are for continuous film or print reading,
some are automated for use w/ dies & inks that have little to do w/
photography, & some are for digital photography uses, & they all cost
thousands new. In order to have any idea what to buy, I need the specs
& / or advertising data when they were new. But I have no idea of
anything. I usually don't get this confused about a technology. But
this is amazing.
I've looked (on line) @ several Besslers, but some appear to have
vacuum tubes. I don't think vacuum tubes are made anymore. But I don't
know how to tell which are solid state from looking on line. I went to
Wikipedia & really wasn't able to find out much. Does any one have a
recommendation how I might sort all this info our & find some solid
data on possible candidates for my search. Or actual recommendations
would be appreciated, but not expected.
BWT where has this group gone? Where ever, I suppose that's where I
should post this.
Thanks, JD


There is a lot to know about densitometers. My guess is that looking
around and talking to various sources would be good advice. They
appear on eBay. In various countries there are photo flea markets or
camera shows. Sometimes they appear there.

I found an old Kodak densitometer for about $20 and played with it.
At the time I thought I wanted a better one. In the end I got a very
full featured modern densitometer for about $50 (a real bargain). For
most of what I do, the Kodak has shown itself to be just fine.

I'm not sure what you are doing, but my impression is that you can
spend a whole lot of money and not necessarily get much more.



Even the basic little ilford one works pretty good for me. I've used it
for when I have changed the filtration but wanted to keep the same
exposure (used it to adjust the f-stop after a filtration change) and
never had a problem. Those can be had for almost nothing on fleabay. I'm
not sure what the OP is wanting one to do for them?

Stephanie
  #2  
Old March 5th 10, 09:50 PM posted to rec.photo.darkroom
Claudio Bonavolta
external usenet poster
 
Posts: 50
Default Color & B&W Densitometers

wrote:
Peter wrote:
On Mar 2, 6:07 pm, jay wrote:
Hi all
I want to buy a used color & B&W Densitometer that will work in both
the transmission & reflected mode @ a fairly low price. (Say $400)
I've visited X- Rites web site, & leave w/ my head spinning. I have
the impression that some are for continuous film or print reading,
some are automated for use w/ dies & inks that have little to do w/
photography, & some are for digital photography uses, & they all cost
thousands new. In order to have any idea what to buy, I need the specs
& / or advertising data when they were new. But I have no idea of
anything. I usually don't get this confused about a technology. But
this is amazing.
I've looked (on line) @ several Besslers, but some appear to have
vacuum tubes. I don't think vacuum tubes are made anymore. But I don't
know how to tell which are solid state from looking on line. I went to
Wikipedia & really wasn't able to find out much. Does any one have a
recommendation how I might sort all this info our & find some solid
data on possible candidates for my search. Or actual recommendations
would be appreciated, but not expected.
BWT where has this group gone? Where ever, I suppose that's where I
should post this.
Thanks, JD


There is a lot to know about densitometers. My guess is that looking
around and talking to various sources would be good advice. They
appear on eBay. In various countries there are photo flea markets or
camera shows. Sometimes they appear there.

I found an old Kodak densitometer for about $20 and played with it.
At the time I thought I wanted a better one. In the end I got a very
full featured modern densitometer for about $50 (a real bargain). For
most of what I do, the Kodak has shown itself to be just fine.

I'm not sure what you are doing, but my impression is that you can
spend a whole lot of money and not necessarily get much more.



Even the basic little ilford one works pretty good for me. I've used it
for when I have changed the filtration but wanted to keep the same
exposure (used it to adjust the f-stop after a filtration change) and
never had a problem. Those can be had for almost nothing on fleabay. I'm
not sure what the OP is wanting one to do for them?

Stephanie


If you're talking about the Ilford EM-10, then this is not a
densitometer but an enlarger meter.

A densitometer is a tool that reads a density, can be from a transparent
or opaque media, can be color or B/W. Some are specialized in UV
readings, others for printing (offset, ...).
Typical densitometers:
http://www.xrite.com/product_overview.aspx?ID=278

An enlarger meter, often coupled to a timer, is a tool that helps a
darkroom printer to find the good exposure time.
Typical enlarger meters:
http://www.rhdesigns.co.uk/darkroom/index.html

Claudio Bonavolta
http://www.bonavolta.ch

--- news://freenews.netfront.net/ - complaints: ---
  #3  
Old March 6th 10, 01:21 AM posted to rec.photo.darkroom
Nicholas O. Lindan
external usenet poster
 
Posts: 1,227
Default Color & B&W Densitometers

Some enlarging meters are also very good B&W densitometers:

http://www.darkroomautomation.com/em.htm

If you are enlarging the negatives then the proper place to
read the density is at the enlarger's easel. It gives you
the effective density in your equipment - taking into account
flare and calier effects.

If you are doing zone system calibration then what you want
is the EI and development time that gives perfect prints on
#2 paper in your enlarger, not some arbitrary set of densities.

You also need to find the total exposure to the paper
that results in almost not white and almost but not quite
totally black. The difference in exposure in stops between
these points is equal to the difference in negative density
you want for spanning Zone I to Zone IX.

--
Nicholas O. Lindan
Cleveland Engineering Design, LLC
Cleveland, Ohio 44121


  #4  
Old March 6th 10, 11:36 AM posted to rec.photo.darkroom
Claudio Bonavolta
external usenet poster
 
Posts: 50
Default Color & B&W Densitometers

Nicholas O. Lindan wrote:
Some enlarging meters are also very good B&W densitometers:

http://www.darkroomautomation.com/em.htm

If you are enlarging the negatives then the proper place to
read the density is at the enlarger's easel. It gives you
the effective density in your equipment - taking into account
flare and calier effects.

If you are doing zone system calibration then what you want
is the EI and development time that gives perfect prints on
#2 paper in your enlarger, not some arbitrary set of densities.

You also need to find the total exposure to the paper
that results in almost not white and almost but not quite
totally black. The difference in exposure in stops between
these points is equal to the difference in negative density
you want for spanning Zone I to Zone IX.

--
Nicholas O. Lindan
Cleveland Engineering Design, LLC
Cleveland, Ohio 44121



Absolutely, any enlarger timer that gives an exposure time can be used
as a densitometer or to measure negative contrast too, an example with
my free softwa
http://www.bonavolta.ch/hobby/en/photo/darktools.htm
Which will be enough for the majority of printers, at least with silver
gelatin.

Said that, the use is not exactly the same and some densitometers offer
features that are generally not available in enlarger meters, like
reflection or UV densities measurement which are useful in other processes.

Claudio Bonavolta
http://www.bonavolta.ch

--- news://freenews.netfront.net/ - complaints: ---
  #5  
Old March 6th 10, 03:28 PM posted to rec.photo.darkroom
Jean-David Beyer
external usenet poster
 
Posts: 247
Default Color & B&W Densitometers

Claudio Bonavolta wrote:
Nicholas O. Lindan wrote:
Some enlarging meters are also very good B&W densitometers:

http://www.darkroomautomation.com/em.htm

If you are enlarging the negatives then the proper place to
read the density is at the enlarger's easel. It gives you
the effective density in your equipment - taking into account
flare and calier effects.

If you are doing zone system calibration then what you want
is the EI and development time that gives perfect prints on
#2 paper in your enlarger, not some arbitrary set of densities.

You also need to find the total exposure to the paper
that results in almost not white and almost but not quite
totally black. The difference in exposure in stops between
these points is equal to the difference in negative density
you want for spanning Zone I to Zone IX.

--
Nicholas O. Lindan
Cleveland Engineering Design, LLC
Cleveland, Ohio 44121



Absolutely, any enlarger timer that gives an exposure time can be used
as a densitometer or to measure negative contrast too, an example with
my free softwa
http://www.bonavolta.ch/hobby/en/photo/darktools.htm
Which will be enough for the majority of printers, at least with silver
gelatin.

Said that, the use is not exactly the same and some densitometers offer
features that are generally not available in enlarger meters, like
reflection or UV densities measurement which are useful in other processes.

Claudio Bonavolta
http://www.bonavolta.ch

--- news://freenews.netfront.net/ - complaints: ---


Also, with using an enlarger will not give the same values as a
densitometer. Most densitometers are single diffuse instruments. A few
may be specular or double diffuse. But you know what you have.

Now if you are working for just yourself, and will not compare your
readings with anyone else, this may actually be better than with a real
densitometer.

But if you agree with Ansel Adams, and try to get a net density from
Zone I of your negatives to be 0.1, you probably will not know that
using an enlarger. You would need a calibrated step wedge to calibrate
the enlarger "meter" and it would drift around a lot.. My densitometer
has a beam splitter in it that sends half the light direct to a
photodetector and the other half through the negative under test to
another photodetector. The signals are routed through a differential
amplifier. This compensates for changes in temperature, changes in line
voltage, differences from one light source to another, aging of the
light source, ... . Typically, enlargers have none of this.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey
http://counter.li.org
^^-^^ 09:20:01 up 45 days, 10:40, 3 users, load average: 4.62, 4.45, 4.41
  #6  
Old March 6th 10, 05:58 PM posted to rec.photo.darkroom
Nicholas O. Lindan
external usenet poster
 
Posts: 1,227
Default Color & B&W Densitometers

"Jean-David Beyer" wrote

But if you agree with Ansel Adams, and try to get a net density from Zone
I of your negatives to be 0.1


There is nothing sacred about that 0.1 OD number - that's just the
number AA found for his film, development technique, preferred
paper, enlarger and densitometer.

If one is trying to fit the film to the paper - AA's original
intent with the ZS - then there will a different number as one
isn't using the same paper, not to mention film, developers
and all the rest and one's criteria for an 'ideal' print will
be different.

It is equally possible the right number for one's own process
will be 0.05 or 0.20 - it is going to vary enormously with the
toe response of the film, the shoulder response of the paper
and how much shadow contrast - how far up the shoulder and
down the toe - one considers best.

As ZS speed testing invariably ends up with an EI that is roughly
1/2 of the ISO value it can be seen that AA liked more shadow
detail than the ISO standard assumes. With modern films, and their
capacity for overexposure, most photographers agree with AA and
rate their film at 1/2 the ISO speed - even if they have never
gone near the ZS.

At very low densities the readings from a bench densitometer
and an easel densitometer (AKA DA enlarging meter or one of the
old Eseco meters) will be identical.

You would need a calibrated step wedge to calibrate the enlarger "meter"


Er, I sell the meters to folks who make step tablets -
they use them for calibrating the tablets.

and it would drift around a lot.


Zilch. Nada. If you have the right meter...
You need a reasonably stable light source in the enlarger
- a standard incandescent source and a ferro voltage
regulator provides very steady light after everything
warms up.

My densitometer has a beam splitter in it that sends half the light direct
to a photodetector ...


I have been designing spectrophotometers for clinical
chemistry for 30 years now. They measure to 0.00003 OD
absolute with no drift.

... This compensates for changes in temperature


Put a wratten ND filter in the light path and you can
use the density readings for telling the temperature -
the filter's OD changes with temperature.

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http://www.darkroomautomation.com/da-main.htm
n o lindan at ix dot netcom dot com


  #7  
Old March 7th 10, 02:41 PM posted to rec.photo.darkroom
Jean-David Beyer
external usenet poster
 
Posts: 247
Default Color & B&W Densitometers

Nicholas O. Lindan wrote:
"Jean-David Beyer" wrote


We seem to be talking at cross purposes.

But if you agree with Ansel Adams, and try to get a net density from Zone
I of your negatives to be 0.1


There is nothing sacred about that 0.1 OD number - that's just the
number AA found for his film, development technique, preferred
paper, enlarger and densitometer.


I know. That is why I said "if". I actually aim at a net density of 0.25
to 0.3 for Zone I in my work.

If one is trying to fit the film to the paper - AA's original
intent with the ZS - then there will a different number as one
isn't using the same paper, not to mention film, developers
and all the rest and one's criteria for an 'ideal' print will
be different.


True.

It is equally possible the right number for one's own process
will be 0.05 or 0.20 - it is going to vary enormously with the
toe response of the film, the shoulder response of the paper
and how much shadow contrast - how far up the shoulder and
down the toe - one considers best.

As ZS speed testing invariably ends up with an EI that is roughly
1/2 of the ISO value it can be seen that AA liked more shadow
detail than the ISO standard assumes. With modern films, and their
capacity for overexposure, most photographers agree with AA and
rate their film at 1/2 the ISO speed - even if they have never
gone near the ZS.


Yes. Another reason to use more density for Zone I in the negative is
because modern papers are capable of much greater density (e.g., 2.2)
than older papers (e.g., 1.7). But if you expose enough to get that
density in the darkest areas, all the higher zones are too dark, and if
you develop more to get Zone V to match (more or less) the 18% gray
card, the contrast is too high. Hence, expose more.

At very low densities the readings from a bench densitometer
and an easel densitometer (AKA DA enlarging meter or one of the
old Eseco meters) will be identical.


Maybe so. I was thinking of those who rely on their enlarger's light
source as being stable, producing sinigle-diffuse illumination, etc.
Maybe you get that with a cold light head (though they drift a lot, even
the Zone VI stabilized ones).

You would need a calibrated step wedge to calibrate the enlarger "meter"


Er, I sell the meters to folks who make step tablets -
they use them for calibrating the tablets.


I cannot argue with what you do. If using an enlarger to calibrate those
step tablets were satisfatory, they would not be using your meters.

and it would drift around a lot.


Zilch. Nada. If you have the right meter...
You need a reasonably stable light source in the enlarger
- a standard incandescent source and a ferro voltage
regulator provides very steady light after everything
warms up.


I used to have the use of an old Macbeth densitometer, one with vacuum
tubes in it. It drifted all the time, even after 30 minutes of warm-up.
I had to calibrate it for each measurement. The one I bought (TD-901)
seems all solid state and is stable in less than a minute (after the
bulb warms up). The old one may have been a TD-101 something like that.
Analog readout.

My densitometer has a beam splitter in it that sends half the light direct
to a photodetector ...


I have been designing spectrophotometers for clinical
chemistry for 30 years now. They measure to 0.00003 OD
absolute with no drift.


Of course, the requirements for clinical (and research) chemistry are
much more strict that for routine photographic use.

... This compensates for changes in temperature


Put a wratten ND filter in the light path and you can
use the density readings for telling the temperature -
the filter's OD changes with temperature.

Back when I got my Macbeth densitometer, it seemed easier than all the
things I would have to do to make an enlarger and an enlarging meter do
the job.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 08:20:01 up 46 days, 9:40, 3 users, load average: 4.39, 4.43, 4.53
 




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